Lifting jack



Feb. 24, 1925.

G` STEELE LIFTING JACK Filed Aug. 18, 1924 @Memup Patented Feb. 24, 1925.

y unirse 'GGGE ois cononirno'.

LJFTINGI Jack.

-Jippneaun-fneanugust:1s, 1924. seri-aint. vsegsss;

radohaveinventedva newvand., useful Lift,-

ing J ack, of which the following. is a specification.

The present invention'. relatesl to lifting i jacks, the primaryobject. ofthe invention being to. provide a jack of* a' novel telescoping construction including a. plurality vof movingparts, andk aplura-li-ty l'of fratcheted parts, `therebyf increasing the li'rftingl ratio of the jack'` and. consequently incrasingf the liftingjcapacity. of thejackoverfthe Ajacks nowiuuse. Y,

With; theA foregoing, and other. objects, in viewwhich will appear asthe description proceeds, the 4inventiony resides in thel combination and. arrangement of partsgand. in thel details of construction.,hereinafter described f andl claimed, it` being. kunderstood that changes inthe precise embodiment of the invention herein' disclosed, may` be made withinv the: scope of.V what is: claimed, without vdeparting from the spirit. offtheinven'.- tion.

lReferring to 'the drawing Figure 1 is a longitudinal sectionalgview through a jack constructed 4in accordance with the present "inventionland sli-owing the location of the pawls priorto their first movements in lifting.

Figure 2 is a longitudinal sectional view disclosing the locations of the pawls at the end of one stroke of the operating lever.

Figure 3 is a sectional view taken on line 3-3 of Figure 1.

Referring to the drawing in detail, the jack includes a base indicated at 5 which may be of any desired construction. Formed inte ral with the base and extending upwarly therefrom, is a hollow support 6 formed with a plurality of teeth 7 and arranged along one wall thereof.

Positioned in the hollow support 6 and adapted to operate therethrough, is a lifting post 8 which is also formed with teeth 9 extending throughout the'length thereof, the teeth 9 being disposed in a direction opposite to the teeth 7 formed exteriorly of the hollow support for purposes to be hereinafter more fully described.

The lifting post 8 is supplied with a head 10 to be positioned under an article to be lifted,l the head lObeing; relativelylargesothat thesame' will notslipor move with respect" to the` article being lifted.

Forming a.. part ofvthe jack isa' hollow body portionl 11 that extendslaterlly and as shown is provided with a-tubular portion 12 lformed with slioulders 13 toengagef the upperedge of the membersfl, over which the tubular-v portion 12 iss-positioned. fllhe member- 12 is `formed" with a 4slotted portion through,whichflthe pawls, designed to acl complishtheliftingresult operate. y

The lifting-iban is'indicatedia-t 1 4 and has one end ,thereof .pivotally supported'within the body portion at 15,.,thepawlf1`6fwhicli cooperates withv the teeth',v 9. of. the',li ftinfg 'bar`8 being, pivotally connected to the bar :Lfiat17.4 Y

li'votally` mountedwithin the body- 11 at 1-1 isf-afpawlJ 18 .whichf-also.cooperateswith the teeth. 9 tof hold the-lifting bar'` 85 when the same,hasbeen-raised; byf the pawlv 16; The ,pawl119 isf also pivotallyA supported within the'body 1,1- at19f andfis Iadapted, to engage the teeth f7 ,ofl the member 6 to 1- sup,- port the weightfofthebody 11after the body-11; has-been lifted by, a stroke'ofthe bar,14f p,

MountedV on 4the bar-14v isarelativelyv lon-g paw-l .20 .thatlalso' engages theY teeth' T-,to lift the body` portionY upon' a downward move'- ment ofthe outer end ofthe bar 14.' From the foregoing it will be obvious that upon the downward movement of the outer or free end of the bar 14, the pawl 16 contacting with the teeth 9 of the bar 8 will oper# ate to lift the bar 8, and at the same time, the downward movement of bar 14 will cause pawl 2() to engage teeth 7 on member 6 and lift body portion 11.

Pivotally supported by the body portion 11 is a link member indicated at 21 to which link member is pivotally connected link members 22 and 23 respectively which carry link members 24 and 25 respectively at their outer or lfree ends. A spring member indicated at 26 connects the relatively long pawl 20 with the free end of the link memer 24 while the spring member 27 connects the link member 19 with the link member 22 at a point adjacent to the pivot pin that connects the links 22 and 24.

The pawl 16 has connection with the link member 23 by means of the spring member 28, while the pawl 18 has connection with the link member 25 by means of the spring member 29. As shown the link members24 and 25l move between the ribs 25. It is to be understood that the spring members are secured to the pawls so that when the pawls are moved 'in one direction, thel spring members will be bowed and placed under tension to cause the pawls to move into close engagement with the teeth associated therewith. Connected with link member 21 and extending through slot 21 is a shaft 30 provided with a finger piece 31 at its outer endso that by moving the finger piece, the link member 21 may be adjusted to control the movements of the 'spring members.

The operation of the jack is as follows:

Assuming that the jack has been positioned under an object to be raised, the lifting bar beingin a position as illustrated by Figure 1 of the drawings. It will be obvious that upon a downstroke of the outer end of the bar V111, the pawl 16 will lift the bar- 8, and when the bar 14 has been moved to the limit of its downward movement, and the forward end of the bar has been raised, the movement causes the link members 16 and 18 to move downwardly in a vertical plane to the end that the spring members 28 and 29V are bowed causing the pawls'18 and 16 to move into engagement with the teeth of the bar 8 to hold the bar 8 against downward movement. Upon the next stroke o the bar 14 the bar 8 will be againlifted, which operation is repeated until the bar 8 has reached the desired height. Y If it is Adesired to release the jack and lower the object lifted thereby, it is only necessary to turn the finger piece y31 to a position as indicated by Figure 2 `of the drawings, whereupon an upward movement of the bar 14, or outer end thereof will result in the bar 8 being lowered, and when the bar 14 has reached the limit of this Ystroke it follows that the spring 29 is placed with that described as the operation ofthe pawls 16 and 18.

I claim In a double lifting jack, a base, an -upwardly vextended tubular support having teeth lformed thereon, a body portion having a hollow section fitted over the tubular support, a lifting post movable within the tubular support and having downwardly extending teeth, a lifting-bar having one end thereofI pivotally mounted within the body portion, pawls pivotally` connected Withfthe lifting bar and disposed on opposite sides of the support for the lifting bar, said pawls adapted to move the post and bodyl portion vertically when the lifting bar is reciprocated, and supporting pawls cooperating with the teeth to prevent reverse movement of the post and body portion.

In testimony that' I claim the foregoing as my own, I have hereto aflixed my slgnature in the presence of two witnesses.

GEORGE STEELE. Witnesses:

J oHN G.TnoMrsoN, f

J. M. HALL. l 

